Access Network System, Access Equipment, Arp Proxy Method and an IP Bridging Forwarding Method

1. An access network system, comprising: one or more access network edge nodes, each of which being connected with one or more access nodes; and each of the access nodes comprising at least one of the following: an access node supporting layer-3 routing, an access node supporting layer-2, an access node supporting IP bridging, and an access node supporting address resolution protocol proxy; and at least one access node of the one or more access nodes, connected to a customer premises network (CPN) in a digital subscriber line (DSL) access technique or a passive optical network (PON) access technique, and configured to enable a user terminal in the CPN to access to the access network system, wherein the access node is configured to communicate with another access node in the access network system; wherein the access node is configured to proxy-forward an address resolution protocol message and store an IP bridging forwarding table; wherein the access network edge nodes are connected with the access nodes in at least one of the following networking modes: star, tree, chain, and dual-ring, wherein in the case of unicast service, the access network edge nodes are connected with the access nodes in a star or tree networking mode; and in the case of multicast or broadcast service, the access network edge nodes are connected with the access nodes in a chain or dual-ring networking mode; wherein the IP session information in the IP bridging forwarding table comprises: a user-side physical port, a user IP address, and a user MAC address; the IP service connection information in the IP bridging forwarding table comprises a MAC address of the access network edge node; and wherein the IP service connection information further comprises at least one of the following information: a network-side physical port and a virtual local area network identifier.

2. The access network system according to claim 1 , wherein user data is transmitted directly between the access nodes to support communication between users of different access nodes; and if a failure occurs between one of the access nodes and one of the access network edge nodes, the one of the access node is connected with one of the access network edge node via another access node.

3. An access device in an access network system, wherein the access device is connected to a customer premises network (CPN) in a digital subscriber line (DSL) access technique or a passive optical network (PON) access technique, comprising: a user-side port module, configured to communicate with a user terminal in the CPN; a network-side port module, configured to communicate with an access network edge node; wherein the access network edge node is connected with one or more access devices in at least one of the following networking modes: star, tree, chain, and dual-ring, wherein in the case of unicast service, the access network edge nodes are connected with the access devices in a star or tree networking mode; and in the case of multicast or broadcast service, the access network edge nodes are connected with the access devices in a chain or dual-ring networking mode; an access device-side port module, configured to communicate with another access device in the access network system; an address resolution protocol proxy module, which is connected to the user-side port module, the network-side port module and the access device-side port module, configured to proxy-forward an address resolution protocol message; and an IP bridging forwarding module, which is connected to the user-side port module, the network-side port module and the access device-side port module, configured to forward a packet and store an IP bridging forwarding table; wherein the IP session information in the IP bridging forwarding table comprises: a user-side physical port, a user IP address, and a user MAC address; the IP service connection information in the IP bridging forwarding table comprises a MAC address of the access network edge node; and wherein the IP service connection information further comprises at least one of the following information: a network-side physical port and a virtual local area network identifier.

4. The access device according to claim 3 , wherein if the access device receives an address resolution protocol request, the address resolution protocol proxy module in the access device is configured to forward the address resolution protocol request to a next access device, and forward a Media Access Control (MAC) address of the access device in an address resolution protocol response to a sender of the address resolution protocol request.

5. The access device according to claim 3 , wherein in the IP bridging forwarding table of the access device, the item of the user MAC address is a MAC address of a previous access device or user terminal connected with the user-side physical port; or in the IP bridging forwarding table of the access device, the item of the MAC address of the access network edge node is a MAC address of a next access device or network edge node connected with the network-side physical port.

6. The access device according to claim 5 , wherein if the access device receives a packet, the access device is configured to search in the IP bridging forwarding table according to the IP address in the packet to obtain at least one of the IP session information and/or the IP service connection information, update MAC frame header information in the received packet according to the at least one of the IP session information and/or the IP service connection information, and forward the updated packet to a next access device.

7. An address resolution protocol proxy method in an access network system, applied to address resolution protocol proxy between a first access node and a second access node of multiple access nodes, wherein the access network system comprises one or more access network edge nodes, each of the access network edge node is connected with one or more access nodes in at least one of the following networking modes: star, tree, chain, and dual-ring, wherein the access network system provides both a unicast service and either a multicast service or broadcast service, in the case of unicast service, the access network edge nodes are connected with the access nodes in a star or tree networking mode; and in the case of multicast or broadcast service, the access network edge nodes are connected with the access nodes in a chain or dual-ring networking mode; the method comprising: forwarding, by the first access node, an address resolution protocol request from an address resolution protocol requestor to the second access node, and sending, by the first access node, a media access control (MAC) address of the first access node in a first address resolution protocol response to the address resolution protocol requestor; and sending, by the second access node, the MAC address of the second access node in a second address resolution protocol response to the first access node.

8. An IP bridging forwarding method in an access network system, applied to IP bridging forwarding between a first access node and a second access node of multiple access nodes, wherein IP bridging forwarding tables are created in the first access node and the second access node respectively, wherein the access network system comprises one or more access network edge nodes, each of the access network edge node is connected with one or more access nodes in at least one of the following networking modes: star, tree, chain, and dual-ring, wherein in the case of unicast service, the access network edge nodes are connected with the access nodes in a star or tree networking mode; and in the case of multicast or broadcast service, the access network edge nodes are connected with the access nodes in a chain or dual-ring networking mode; the method comprising: searching, by the first access node, an IP bridging forwarding table thereof according to an IP address in a received packet to obtain at least one of IP session information and IP service connection information; updating, by the first access node, MAC frame header information in the received packet according to at least one of the IP session information and the IP service connection information; forwarding, by the first access node, the updated packet to the second access node; wherein the IP session information in the IP bridging forwarding table comprises: a user-side physical port, a user IP address, and a user MAC address; the IP service connection information in the IP bridging forwarding table comprises a MAC address of the access network edge node; and wherein the IP service connection information further comprises at least one of the following information: a network-side physical port and a virtual local area network identifier.

9. The IP bridging forwarding method according to claim 8 , wherein the first access node obtains a MAC address of a user device via a dynamic host configuration protocol message initiated by a user device, to create the IP bridging forwarding table thereof.

10. The IP bridging forwarding method according to claim 8 , wherein in the IP bridging forwarding table of the second access node, the item of the user MAC address corresponding to the user-side physical port connected with the first access node is the MAC address of the first access node.

11. The IP bridging forwarding method according to claim 10 , wherein in the IP bridging forwarding table of the first access node, the item of the MAC address of the access network edge node corresponding to the network-side physical port connected with the second access node is the MAC address of the second access node directed to the access network edge node.

12. The IP bridging forwarding method according to claim 11 , wherein if the packet is sent from a user terminal to the access network edge node, the IP bridging forwarding method comprises: searching, by the first access node, in the IP bridging forwarding table according to a source IP address of the packet from the user terminal to obtain the network-side physical port, the virtual local area network identifier and the MAC address of the access network edge node; updating, by the first access node, a destination MAC address of the packet with the MAC address of the second access node, updating a source MAC address of the packet with the MAC address of the first access node, and adding or updating the virtual local area network identifier of the packet; and forwarding, by the first access node, the updated packet to the second access node via the obtained network-side physical port.

13. The IP bridging forwarding method according to claim 11 , wherein if the packet is sent from a user terminal to the access network edge node, the IP bridging forwarding method comprises: searching, by the second access node, in the IP bridging forwarding table according to a source IP address of the packet from the user terminal to obtain the network-side physical port, the virtual local area network identifier and the MAC address of the access network edge node; updating, by the second access node, a destination MAC address of the packet with the MAC address of the access network edge node, updating a source MAC address of the packet with the MAC address of the second access node, and adding or updating the virtual local area network identifier of the packet; and forwarding, by the second access node, the updated packet to the access network edge node via the obtained network-side physical port.

14. The IP bridging forwarding method according to claim 12 , wherein if the packet is sent from the access network edge node to the user terminal, the IP bridging forwarding method comprises: searching, by the second access node, in the IP bridging forwarding table according to a destination IP address of the packet from the network-side physical port to obtain the user-side physical port and the user MAC address; updating the destination MAC address of the packet with the MAC address of the first access node, updating the source MAC address of the packet with the MAC address of the second access node; and forwarding, by the second access node, the updated packet to the first access node via the obtained user-side physical port.

15. The IP bridging forwarding method according to claim 12 , wherein if the packet is sent from the access network edge node to the user terminal, the IP bridging forwarding method comprises: searching, by the first access node, in the IP bridging forwarding table according to a destination IP address of the packet from the network-side physical port to obtain the user-side physical port and the user MAC address; updating the destination MAC address of the packet with the user MAC address, updating the source MAC address of the packet with the MAC address of the first access node; and forwarding, by the first access node, the updated packet to the user terminal via the obtained user-side physical port.

16. The access network system according to claim 3 , wherein in the IP bridge forwarding table of the access device, the item of the MAC address of the access network edge node is a MAC address of one of a next device and network edge node connected with the network side physical port.